The present invention relates to a miniature antenna for use with a portable miniature radio transceiver or the like.
Conventionally, loop antennas of monopole antennas are widely employed for portable miniature radio transceivers and they are inevitably adapted for operation primarily in the plane of vertical polarization. Vertically polarized electric waves transmitted from the transmitting station toward the receiver are partly rendered into a horizontally polarized component under the influence of surrounding conditions, and in general, the vertically polarized component is received with an intensity several times higher than the horizontally polarized component. The distance range of communication significantly differs depending on whether the plane of polarization of the receiving antenna is held to be vertical or horizontal with respect to such incoming electric waves. For example, in case of a pager receiver using a loop antenna, its receiving sensitivity markedly differs depending on whether the receiver is placed longitudinally or sideways.
Conventional portable miniature radio transceivers have not taken any counter measures to this disadvantage.
For instance, the prior art pager receiver is equipped with an antenna in such a manner that the receiving sensitivity is maximum when it is carried vertically in a breast pocket of user's shirt, but in practice, it is often carried in a pocket of a jacket, a bag, handbag, or the like. In such a case, the pager receiver is usually laid at its side, that is, it is kept in the direction in which the directivity is the lowest, resulting in the coverage of communication being seriously impaired.